After 60 to 70 day high rainfall, farmers in many area were significantly delayed in getting back into the field to spray soybeans. Even those who could get in the field got chased out many times by rain or a pop-up storm. In many instances the environment in which the spraying took place wasn’t ideal for good coverage or control of weeds.

I have gotten many calls this spring on what to do about delayed spraying, ineffective weed control and, especially complaints about waterhemp and marestail control. It has been a losing battle in some areas and in some fields. Many farmers have tried multiple applications, when they could travel the fields, with varying products, in an attempt to get the job done. In most cases they have consulted the advice of retailers and product representatives in trying to make these decisions. They have also, in some instances, relied on coffee shop talk on what seems to be working and what hasn’t.

Pictured is the result of relying on sources of information that are less than reliable when making weed-control decisions. This field had been sprayed three times. Without going into a lot of details-between the products used, the growing environment and the equipment-used, the results were a lot of crop damage despite the clean field.

Every place that there was boom overlap, there was reduced or no stand of soybeans. On the end rows where one boom didn’t shut off completely, we have semi-circle streaks. The result is that there are many “hot spots” across the field where we have 2x the rate due to the overlap. Also, with the different chemistries applied we have plant damage and death in many areas of the field as well.

Desperate times lead to mistakes. The result of these applications will be that this field will go back to soybeans in 2016.


While this is an extreme case, this story could be repeated on a lesser scale in many other places. This is why we always follow label directions and rates when we apply an herbicide. It is also why we rely on product information from trusted sources, not coffee shop talk.

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About the Author: Kelly Robertson

Kelly Robertson has been a soil fertility agronomist and precision agriculture consultant since 1989 and also spends time in farm/agronomy management roles for farms in Southern Illinois. In 2012, Kelly and his wife Lori started Precision Crop Services in Benton where they provide agronomic services for their customers including soil testing, crop scouting, data analysis, GPS/GIS services including variable rate seeding and fertility recommendations as well as farm and agronomy management for their customers. He is a Certified Professional Agronomist, Certified Crop Advisor, Certified 4R Nutrient Management Specialist, 2015 Illinois Soybean Association Double-Crop Specialist, 2016 Illinois CCA of the Year and the 2021 Illinois Soybean Assoc. Dave Rahe Excellence in Soils Consulting Award winner.